The Compressor/Fan Properties window offers the option of Sizing a compressor/fan. By entering either a volumetric or mass flow rate, the total developed pressure is calculated and displayed in the Compressor/Fan section of the Output Window. By assigning a flow to a compressor/fan, determining the compressor/fan size requirements is straightforward.

To size a compressor/fan, first specify if the junction is a centrifugal compressor or fan and then select the Sizing option for the Compressor/Fan Model.

Specify the parameter that should be used for the sizing. The parameters include:

• Volumetric Flow Rate - Fix the volumetric flow rate through the compressor/fan.

• Mass Flow Rate - Fix the mass flow rate through the compressor/fan.

• Head Rise - Fix the head rise through the compressor/fan. Note that the density used when fixing the head rise through a compressor/fan is that of the fluid at the suction of the turbomachine.

• Pressure Rise - Fix the pressure rise through the compressor/fan.

• Compression Ratio - This option is only available for compressors, and it allows you to fix the compression ratio of the compressor. This ratio is important because it directly affects the efficiency of the compressor, and it is calculated using the equation:

Problems with Compressor/Fan Sizing and Using a Flow Control Valve

Using the Sizing feature on a Compressor/Fan Properties Window with a Flow Control Valve (which also fixes flow rate) downstream of the compressor/fan junction results in a Reference Pressure error - the system no longer has a unique solution. Read more about this in Role of Pressure Junctions - Detailed Discussion.